1. Field of the Invention
The present invention relates to a process of regenerating articular cartilage surface which has been damaged, destroyed, or has otherwise become defective, thereby alleviating pain, stiffness, and other difficulties associated with a defective articular cartilage surface in a joint.
2. Description of the Related Art
Articular cartilage, the thin, fragile tissue layer covering the ends of bones, allows healthy joints to move freely and without pain. Many arthritic diseases and many degrees of trauma can, however, cause destruction or deterioration of this fragile layer, leading to pain, joint stiffness, and even crippling. From ancient times until the present, it has commonly been believed that this fragile surface, once lost, could never be restored. Attempts made in the past to regenerate or otherwise repair articular cartilage have been failures, thereby directing medical science to the development of substitutes and abandoning the potential for regeneration. Many substitutes have been developed to replace the articular cartilage joint surfaces, and these substitutes require implantations by surgery. Earlier substitutes included fascial transplants or transplants of entire joints such as the knee; however, the majority of these transplants were failures. More recently, medical science has developed implants which utilize metal and plastic components, but these are very costly because of the complicated implant components, the prolonged and repeated hospitalizations required for the surgical implantation of the components and the long periods of rehabilitation. In addition, many cases require one or more revision surgeries to replace defective, loose or infected implants. Most often, full motion and full activity are not achieved with the use of these implants. Further, the general discomfort associated with utilizing such implants makes an alternative method all the more desirable. The biological action of somatotropin acting in this process has been the subject of the applicant's research. The use of growth hormone in this manner is novel; heretofore, growth hormone has always been used clinically to enhance the growth of children with short stature. Somatotropin may have other effects on other organ systems but in the instant patent, the specific actions of somatotropin related cartilage growth which have been identified by Dunn's research are utilized herein. The major targets of somatotropin activity for cartilage regeneration are nests of stem (pleuripotential) cells in the marrow and the vascular system--specifically the vascular sinusoids located at the cartilage bone interface (sub-chondral bone) and the endothelial cells located therein.
The process of regeneration is biphasic. The initial phase, called Morphogenic Phase I, relies on the ability of growth hormone to stimulate proliferation of stem cells in the marrow, and the additional ability of somatotropin to form vascular glomular sinusoids 40' (Glomeruloids) from pre-existing single lumen vessels 40" in the sub-chondral bone. The second phase, the Generative Phase, involves the transfer of stem cells from the marrow to the Glomeruloids. Additional stem cells may be provided directly from the endothelial cells located in the vessel walls of the Glomeruloids. Within these Glomeruloids, the stem cells are transformed into cartilage cells first by transforming into prechondrocytes and then further transforming into chondrocytes. From the Glomeruloid layer, the chondrocytes pass upward and outward to form a new cartilage layer. The matrix of the cartilage layer is simultaneously produced by the new chondrocytes. The dosage of growth hormone to be applied in the single dosage is proportional to the body weight of the patient. The dosages were described above.
Heretofore, growth hormone has been used to augment the height of growth deficient children. The method of this invention relies on a novel use of growth hormone (somatotropin). There is no reliance on transplantation of tissue and thus all of the detrimental conditions of rejection, immune reaction, and failure are avoided. Until the present invention, growth hormone has never been used to regenerate tissue such as articular cartilage.
The method of the present invention is specifically adapted to initiate natural regeneration of articular cartilage on the joint surface through comparatively minor surgical procedures and the injection of one or more dosages of purified growth hormone (somatotropin) to initiate regeneration of and maintain the quality and quantity of articular cartilage. Accordingly, the method of the present invention provides a much needed improvement in the treatment and elimination of ailments associated with the deterioration or destruction of the articular cartilage surface of a joint.